Hottest week of year meets record-breaking heatwave

Horseshoe Lake in the Mammoth Lakes Basin is normally full right up to the edge of the trees in this photo but a low snowpack and record-breaking heat this spring and summer have left the lake high and dry. 

The Eastern Sierra is in for one, long hot week as an incoming heatwave meets what is statistically the hottest week of the entire year.

In other words, the first half of July tends to be the warmest few weeks of the year on average and, an incoming heat wave will likely shatter records as well.

On top of that, the heatwave, forecast to cover much of the Western United states, will actually be centered on top of the Central Sierra, which is where the Eastern Sierra is located.

And while the region did not suffer from large wildfires during the most recent heatwave due mostly to wetting rains that came with the storms – despite thousands of lightning strikes and dozens of small fires – the incoming heat wave looks to be dry and accompanied by at least some wind.

“At least for Northern and Central California will see another potentially record-breaking heat wave with little hope for any monsoon moisture before mid-month,” said Mammoth’s forecaster, Howard Sheckter. “Only heat-related, isolated thunderstorms can be expected over the highest elevations at this time; no significant rain.”

“This weekend, Mammoth Lakes has one of those rare opportunities to break 90 degrees,” he said. “Other 90-degree-plus opportunities will continue into early next week. This only occurs during the very hottest summers, without monsoonal flow.”

Bishop will also break records – maybe a lot of them.

“As noted, this heat wave comes during the climatically warmest week of the year,” he said. “The all-time record high in the Bishop area (110 F) was the 10th of July,” he said. “The predicted high for this Saturday and Sunday is 109 F,” he said. “However, highs of 107 to 109 at the Bishop airport are forecasted beginning this Wednesday through next Monday. The only consolation is that this is a dry pattern with relatively low dew points for this time of the year, so swamp coolers will do their job.”

As such, firefighters up and down the state are bracing and getting ready for bad news – and hoping for good news.

So, when will it end?

“It is very possible that this crazy heat wave may last well into next week,” he said, or even later.  He said there are no clear signals yet indicating a break in the heat.

 That does not mean it will not break; it’s just there are no clear indications of when it will.

“Longest range models continue retrogression of the upper high, with only some, not all, model runs hinting of an easterly wave injecting moisture up into Eastern California just after mid-month,” he said. “So, what we have here is another protracted heat wave for the deserts of Mono and Inyo counties with little if any relief from thunderstorms expected in the foreseeable future.”

The reason it will be so hot so long is that there are a series of patterns adding up, all pointing toward excessive heat lasting for a while, he said.

“This heat wave has legs, which includes a ‘drought feedback’ system due to a lack of snow-cover in high elevations, already dry and brittle trees and other fuels, very dry soils and more,” he said.

That means not only will Mammoth be as high as 90-degrees or more, but Bishop may break all-time records for staying 100-plus degrees at the Bishop airport over the next two weeks,” he said. 

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